Hematopoietic cell transplantation is a component of standard therapy for many malignant hematological diseases and is actively being investigated for use in treating non-hematological malignancies and autoimmune diseases, preventing the rejection of solid organ transplants and delivering gene therapy and immune therapy. The use of highly purified hematopoietic stem cells, the only cells responsible for hematopoietic reconstitution, greatly reduces the risks associated with transplantation by eliminating cancer cells and T-cells without increasing the time to engraftment relative to unpurified populations. We propose to build and biologically evaluate a prototype of a novel hematopoietic stem cell sorter that will be immediately applicable to current HCT therapy and will expand the potential use of this treatment to other diseases. The modular cell sorting device is the product of collaboration between two companies, each with unique expertise. It incorporates recent advances in technology that have already been proven in other fields and can achieve sorting speeds of up to 50-100 times that of current fluorescence activated cell sorters. In addition, this device has a self-contained, disposable chip architecture that is substantially less expensive, safer (vis a vis contamination) and more efficient that current technology.